Fuse



July 15, 1941.

w. o. SCHULTZ 2,249,178

FUSE

Filed April 24, 1939 4 Sheets-Sheet 2 v ,aa

676i n m j v INVENTOR. W/u/AM 0. Ja/z/zrz BY ATTORNEY.

July15, 1941.

w. o. SCHULTZ 2,249,178

FUSE

Filed April 24, 1939 4 Sheets-Sheet 4 INVENTOR. 14 41/444 0. Jaw/0M2 m fi w ATTORNEY.

' Patented July 15, 1941 FUSE William 0. Schultz, South Milwaukee, Wis assignor to Line Material Compa y, South Milwaukee, Wis a corporation of Delaware Application April 24, 1939, Serial N 0. 269,613

16 Claims.

This invention relates to fuses and is particularly directed toan expulsion type of drop-out fuse.

Objects of this invention are to provide a novel type of fuse device which may be of the housed type, and in which a fuse tube normally completes acircuit between upper and lower contacts and, upon blowing. ejects the fuse link and also slides downwardly so that a part of it projects below the lower portion of the housing giving an indication that the fuse has blown.

Further objects of this invention are to provide a slidable type of drop-out fuse in which novel means are provided for very quickly and forcibly extracting any remaining unburned por- .tion of the fuse link, such means causing the fuse link to be withdrawn substantially in line with the fuse tube, thereby overcoming any tendency of sticking due to the link dragging over the end of the tube, and also permitting the use of relatively stiff fuse link leaders.

In greater detail, further-objects are to pro-' vide a flip-out and fuse tube releasing device which is so made that it quickly and forcibly ejects the unburned portion of the fuse link, thereby causing a quick interruption of the circuit within the fuse tube itself, and which thereafter releases the fuse tube and allows the fuse tube to slide downwardly to inoperative position out of the electric circuit.

Further objects are to provide a fuse con- Rossu D struction in which a quick operating flip-out I device is provided forwithdrawing any remaining portion of the fuse link, in which this flipout device, duetto the momentum acquired by it in fuse extracting motion upon rupture of the fuse link,.transmits force to a retaining lever by the momentum of the flip-out device itself and assists in rocking the lever to fuse releasing position. the lever being biased towards fuse releasing position by the weight of the fuse tube and by thepressure of an upper spring contact.

Further objects are to provide a construction in which the flip-out device acts as a spring cushioning means for taking up any slack in the fuse link after refusing and which acts as a cushioning member when the door of the fuse device is suddenly closed, thereby preventing the transmission of any undue stress to the fuse link itself.

Further objects are to provide a drop-out fuse of the sliding type which is so constructed that there is no chance of the fuse sticking in place after the fuse link has been ruptured, in which a complete interruption of the circuit and withthe door and the associated parts detached from "the housing.

Figure 4 is a side elevation of the device.

Figure 5 is a bottom plan view of the structure.

Figure 6 is a sectional view on the line 0-6 of Figure 1'.

Figure 7 is a view of the lower portion ,of Figure 1, showing the parts as they appear after the fuse has blown.

.Referring to the drawings, it will be seen that .the fuse comprises a casing I of porcelain or other suitable material which is provided with hooks 2, see Figure 7, adjacent its lower portion. The hooks removably receive the headed trunnions 3 of a door 4 formed of suitable insulating material, such as a phenolic condensation product. The door is provided with 'an eyelet portion 5 by means of which it may be opened or closed, and with a :web 6 on its inner side having a rounded portion to accommodate the upper cap Lof the fuse tube 8.

The housing carries an upper terminal mem-' ber indicated generallyat 9 and a lower terminal member indicated generally at it. The upper and lower terminal members are provided with conductor receiving portions, as shown, and the conductors may extend outwardly through the usual apertures in the sides of the housing.

The housing is provided with any suitable means, such as indicated at l I, whereby it may be attached to a support. The upper terminal or contact is provided with a contact spring I2 which may be formed of laminated structure, as shown, and one end of the spring may be folded over, as indicated at It in Figure 1. The spring has a flat lower portion that bears firmly against the upper fiat face of the cap I of the upper contact of the fuse tube. This upper terminal is also provided with a pair of relatively heavy spring arms ll, as shown in Figure 2, and these arms are provided with inwardly depressed portions I! which fit around in front of the upper cap 'I of the fuse tube. The arms I do'not bind against the upper cap of the fuse tube.

However, they assist in holding the door in closed bility of binding of I 8 in theevent the fuse tube'should swell, and

position and guardagainst the door being jarred open even if the device is mounted on a support subject to considerable vibration.

The door is also held closed by the lower spring arms. or contact members l6 which have slightly inturned ends H, as shown in Figure 6. The spring arms l6 may be formed of laminated structure, as shown in Figure 6.

' The door rigidly carries a lower contact blockor sleeve l8, see Figures 1, 3, 6 and '7. This sleeve or lower contact of the fuse tube is provided with bevelled portions I! to assist in spreading the spring arms ii of the lower terminal member. The contact I8 is also provided with a rearwardly projecting ear which is positioned 22,'see Figures 1, 3 and 7, which lever in turn pivotally carries a flip-out device 23, see particularly Figures 1 and .7. The flip-out device is mounted upon ,a pivot pin 24 extending across the lower portion of the lever 22, and a spring 25 is loosely'coiled about the pin and bears against the flip-out and against a portion of the lever urging 4 the flip-out towards clockwise in Figure 1.

The flip-out is preferably provided with a slightly rounded front edge portion 28 and with a rounded rear edge portion 21, and with a pair of lips 28 on opposite sides of the rear edge portion rotation, as viewed -These lips are adapted to engage the laterally projecting bottom side portions 22' of the lever 22 after the flip-out hasoperated, as shown in Figure 7. I v

The contact sleeve I8 is provided with stops I 8' for limiting the outward motion of the lever 22.

The lever 22 is'provided with shouldered portions 29 on opposite sides'thereof which are normally positioned below thestops or downwardly projecting portions 30 of the sleeve l8;

The fuse tube 8 is provided with an upper ferrule 3| which is screw-threaded thereon and which is externally threaded to receive'the upper cap [which constitutes the upper contact of the fuse tube. At an intermediate portion the fuse tube carries a metal ferrule 32 which is provided with tapered upper and lower portions as shown in Figures 1 and 7.

This metal sleeve loosely and slidably fits within the sleeve l8 fixedly carried by the door. It is provided to prevent any possithe fuse tubewithin the sleeve insures free sliding of the sleeve under all conditions.

Normally the fuse tube is held in place in it! fuse' tube. through the upper position, as shown in Figure'l, by means of a fuse link which includes the fusible section 23 and a leader 34. The leader extends outward.-

ly through the bottom open end ofthe fuse tube: and is guided through the notch 25 formed in the bottom marginal portion of the fuse tube and extends over the flipper 23:.and upwardly to a position below the thumb screw 3!, the thumb screw-35 being screwed on-a-threaded stem 21 rigidly carried by the lower contact or sleeve l l.-

' The sleeve 32 is locked to the fuse tube by'a transversely extending pin 38 which passes The inturned ends are most clearly shown in Figure5.

'- pivotally carried'by supports at its lower end and 7o. through theisleeve and through a notched porfuse link, the weight of the tube together with the spring pressure exerted by the upper contact spring l2'will rock the lever 22 to the left, as viewed in Figure 1, and thus release the tube for downward sliding motion, the final position of. the parts being shown in Figure 7.

It is to be noted particularly that the flipper 23 in rocking about the pin 24, causes its outer or free end adjacent the bottom of the fuse tube to rock substantially straight downwardly for a portion at least of its stroke and consequently it is Possible to use stiffer leaders with this construction as it does not require the making of a sudden bend in the link when the flipper Operates. W- ticularly in the early portion of the stroke of the flipper.

Additionally, it is to be noted that the flipper executes a very quick'stroke and quickly interrupts the-circuit within the fuse tube and forcibly withdraws the remaining portion of the fuse link and avoids any tendency of sticking or binding of the leader at the lower end of the fuse tube for, as stated, the flipper executes a stroke which is substantially downwardly with reference to the lower end of the fuse tube and thereby projects the link in substantial alignment with the fuse tube.

It is to be noted further as shown in the dotted line position of Figure 7, that the momentum of the flipper when the flipper is brought to rest by the contacting of its fingers 28 with the adjacent portion of the lever 22, assists in throwing the lever 22 to the left, as viewed in Figure 7, and as shown in dotted lines, so that this action assists the action of the fuse tube in disengaging itself from the lever 22.

A further: advantageous result from this construction is due to the fact that inevitably there is some slack in the fuse link when it is clamped beneath the clamp thumb screw". Therefore, if there is any shock imparted to the link by slamming the'door shut. the flip-out device acts as a spring buffer. to relieve or cushion any shock to the fuse link.

It will also be seen that the flipper operates immediately prior to the sliding downwardly of the tube and as there is verylittle inertia to the flipper in comparison to the inertia to the other parts. it is obvious that the flipper will executes very quick stroke and quickly interrupt the circuit in the fuse tube prior .to the breaking of the circuit by the motion of the upper contact cap 1 downwardly away from the upper contact spring l2.

While the flip-out device has been illustrated fuse tube, it is obvious with other types. It is obvious that the flip-out device can be employed whether the construction involves a housed or an unhoused type of Further, the. flip-out device if desired may be carried on the pivot link which pivot link is is pivoted to the fuse tube at its upper end. This ;la st construction is specifically claimed-in my 00- i pending-application Serial'No. 301,350, flied De- 4, 1939, for Fuses.

mourn this invention has be understood that such description is'intended as illustrative rather been described in said flip-out lever.

than limiting, as the invention may be variously embodied and 'is to be interpreted as claimed.

I claim:

1. A drop-out fuse comprising supporting means havinga stationary upper contact and a lower contact, a fuse tube having an upper contact normally engaging. said stationary upper contact and having an open lower end, a fuse link extending from the upper contact of said fuse tube outwardly from the open end and electrically connected to said lower contact, said fuse tube being movably supported from said support and movable from operative to inoperative position, movable latching means adjacent the lower portion of said fuse tube for normally holding said fuse tube against motion from operative to inoperative position, and a flip-out device carried -by said latching means and over which said fuse link is looped, said flip-out device being biased towards fuse link extracting motion and having motion with respect to said latching means independently of any motion of. said latching means.

2. A drop-out fuse comprising supporting means having a stationary upper contact and a lower contact, a fuse tube having an upper contact normally engaging said stationary upper contact and having an open lower end, a fuse link extending from the upper contact of said fuse tube outwardly from the open end and electrically connected to saidlower contact, said fuse tube being movably supported from said supporting means, movable latching means adjacent the lower portion of said fuse tube for normally holding said fuse tube against motion,

, a flip-out device pivoted on said latching means and engaging a portion of said fuse link, and a spring urging said flip-out device towards fuse link extracting motion. said flip-out device withdrawing any unburned portion of said fuse link outwardly from said fuse tube substantially in line with said fuse tube.

3. A drop-out fuse comprising supporting means having astationary upper contact and a lower contact, a fuse tube having an upper contact normally engaging said stationary upper contact and having an open lower end, a fuse a lower contact, tube slidably mounted in said lower contact and having an upper contact adapted to normally engage the upper stationary contact and movable away from said upper stationary contact when said fuse tube slides downwardly, said fuse tube having an open lower end and having a projecting portion, a latching lever mounted on said lower contact and normally engaging said projecting portion to restrain said fuse tube against sliding motion, a spring urged flip-out lever pivotally mounted on said latching lever and located adjacent the lower portion of said fuse tube, and a fuse link extending from the upper stationary contact of said fuse tube to said' lower contact and looped over said latching lever and said flip-out lever.

6. A drop;out fuse construction comprising a support having an upper stationary contact and having a 'lower,.contact. a fuse tube slidable through said lower contact and having projecting portions on opposite sides of said fuse tube,

a U-shaped latching lever pivoted to said lower contact and having shoulders on opposite sides.

normally engaging said projecting portions and restraining said fuse tube against sliding motion,

- a flip-out lever pivoted adjacent the lower porlink extending from th upper contact of said fuse tube outwardly from the open end and electrically connected to said lower contact, said fuse tube being movably supported from said support, movable latching means adjacent the lower portion of said fuse tube for normally v holding said fuse tube against motion, a flip-out device pivoted to said latching means, and a spring engaging said flip-out device and" said latching deviceand urging said flip-out device towards motion with reference to said latching means. I

4. A drop-out fuse,comprising a support having an upperstationary contact and having a lower contact, a' fuse tube slidably mounted in said lower contact and havingan upper contact normally engaging the upper contact of said support and movable away therefrom when said fuse tube slides downwardly, a latching lever normally restraining said fuse tube against sliding, a spring biased flip-out lever pivoted on said latching lever, and a fuse link extending from the upper contact of said fuse tube through said.

construction comprising a stationary contact and tion of said latching lever, a spring. between said latching lever and said flip-out lever urging said flip-out lever towards outward motion, and a fuse link extending from the upper contact of said fuse tube to the lower contact and looped over said flip-out lever, said flip-out lever having a free end adjacent the lower portion of said fuse tube for extracting any remaining portion of the fuse link in a direction substantially in line with said fuse tube.

'l. A drop-out fuse construction comprising an upper and a lower contact, a fuse tube slidably mounted with reference to said contacts, a fuse link normally electrically joining said contacts and extending through said fuse tube and outwardly from the lower end of said fuse tube, a pivotally mounted latching lever having shoulder means, projecting means carried by said fuse tube andnormally engaging the shoulder means of-said pivoted latching lever, a flip-out lever pivotally mounted adjacent the lower end of said latching lever an over which said fuse link is looped, and a spring between said latch lever and said pivoted flip-out lever urging said pivoted vided with an upper contact normally engaging said stationary upper contact, a latching leyer,

said fuse tube and said latching lever having normally interengagingparts to restrain said fuse tube against sliding motion, said latching lever being pivoted" to said lower contact. at a point spaced from :said interengaging parts. whereby the weight of said fuse tube tends to rock said'latching lever to latph releasing position, a spring biased flip-out lever pivotally mounted on the lower portion of said latching lever, and a fuse link extending from the upper contact of said fuse tube outwardly from the lower end thereof to the lower contact and looped over said flip-out lever.

9. A drop-out fuse construction comprising a support having a stationaryupper contact and having a lower contact, a. fuse tube slidably mounted within said lower contact and having an open lower end'and a closed upper end provided with ansupp'er contact normally engaging said stationary upper contact, a latching lever,

said fuse tube and said latching lever having normally interengaging parts to restrain said fuse tube against sliding motion, said latching lever being pivoted to said lower contact at a point spaced from said interengaging parts, whereby the weight of said "fuse tube tends to rock said latching lever. to latch releasing position, a spring biased flip-out lever pivotally mounted on the lower portion of said latching lever, and a fuse link extending from the upper contact of said fuse tube outwardly from the lower end thereof to the lower contact and looped over said flip-out lever, said flip-out lever having a quick fuse link extracting motion independent. of the motion of said latching lever.

10. A drop-out fuse construction comprising a support having a stationary upper contact and having a lower contact, a fuse tube slidably mounted within said lower contact and having an open lower end and a closed upper end provided with an upper contact normally engaging said stationary upper contact, a latching lever,

said fuse tube and said latching lever having normally interengaging parts to restrain said fuse tube against sliding motion, said latching lever beingpivoted to said lower contact at a point spaced from said interengaging parts, whereby the weight of said fuse tube'tends to rock said latching lever to latch releasing position, a spring biased flip-out lever pivotally mounted on the lower portion of said latching lever, and a fuse link extending from the upper contact of said fuse tube outwardly from the lower end thereof to the lower contact and looped over said flip-out lever, said flip-out lever having a quick fuse link extracting motion independent of the motion of said latching lever, and said latching lever being movable outwardly after said flip-out lever has operated to assist in the further extraction of any remaining portion of said fuse link upon rupture of the fuse link.

11. A drop-out fuse construction comprising a support having an upper stationary contact and a lower contact, a fuse tube slidably mounted in said lower contact and having an upper contact shouldered portions adapted to seat back of the inturned ends of the arms of said lower stationary contact, a fuse tube slidably carried by the contact of said door and having an upper contact normally engaging the upper stationary contact, a latching lever pivoted to the contact of said door, said latching lever and said fuse tube having interengaging portions normally restraining said fuse tube against sliding motion, a flipout lever carried by the latching lever and spring urged outwardly with reference to said latching lever, and a fuse link extending from th upper contact of said fuse tube over said flip-out lever to the contact carried by said door.

13. A housed type drop-out fuse comprising a housing having upper and lower'stationary con tacts, a door pivotally mounted on said housing and having a lower contact adapted to engage the stationary lower contact, a fuse tube slidably mounted in the contact of. said door and having an upper contact adapted to engage the upper contact of said housing, at least one of the contacts of said housing having inturned ends adapted to normally prevent opening of said door, a latching lever pivotally mounted on the contact of said door, said latching lever and said fuse tube having normally interengaging portions, a spring pressed flip-out lever pivotally carried by the lower portion of said latching lever and having a free end positioned adjacent the lower end of said fuse tube, and a fuse link extending from the upper contact of said fuse tube over said flip-out lever to the contact carried by said door.

normally engaging said stationary upper contact,

- dered portions spaced laterally from the pivot and normally engaging the projecting portions of said fuse tube, a channel-shaped flip-out lever pivoted adjacent the lower portion of said latching lever, a fuse link extending from the upper contact of said fuse tube to the lower contact and looped over said flip-out lever, and a spring urging said flip-out lever towards outward mo.-. tion with reference to said latching lever.

12. A housed type drop-out fuse comprising a casing having upper and lowerstationary contacts, said lower stationary contact having a pair of spaced arms with inturned ends, a door pivotally mounted on said housing and having a lower contact adapted to enter between the arms of said lower stationary contact and having upper contact of said housing, at least one of the contacts of said housing having inturned ends .adapted to normally prevent opening of said door, a latching lever pivotally mounted on the contact of said door, said latching lever and said fuse tube having normally interengaging portions, a spring pressedfiip-out lever pivotally carried by the lower portion of said latching lever and havinga free end positioned adjacent the lower end of said fuse tube, and a fuse link extending from the upper contact of said fuse tube over said flip-out lever to the contact carried by said door, said upper, contact including a spring normally bearing downwardly on the upper contact of said fuse 'tube'.

15. A housed type drop-out fuse comprising a housing having upper and lower stationary contacts, a door pivotally mounted on said housing and having a lower contact adapted to engage the stationary lower contact, a fuse tube slidably mounted in the contact of said door and having an upper contact adapted to 'engage the upper contact of said housing, at least one of the contacts of said housing having inturned endsadapted to normally prevent opening of said. door, a latching lever pivotally mounted-on the contact of said door, said latching ip'v'el and said fuse tube having normally interengaging portube over said flip-out lever to the ".ct carried by said door, said upper contact including a spring normally bearing downwardly on the upper contact of said fuse tube, said lower stationary contact and the contact carried by said door having means adapted, to interengage and to prevent shifting of said door due to recoil upon blowing of said fuse.

16. A fuse construction comprising-supporting means having a stationary upper contact and a lower contact, a fuse tube having an upper eontact normally eng ng said stationary upper contact and having an open lower end, a fuse link extending from the upper contact of said fuse tube outwardly from the open end and electricallyeonneetedtosaidlowereontaehaflipout device pivoted adjaemt the lower P t on of saidfusetuheandextendingsuhstantiallytransverselyoftheaxisofsaidfusetube,saidflip- "z z z ammonof said fuse link and adapted to extract any unburnedportionofsaidfuselinkwithasubstantialiy downward motion from said fuse tube and being movable withoutreqlfiringthe motion of any other poria'on of the fuse construction,

and means for m said flip-out device towards fuse extracting motion independently of motion of other portions of the fuse construction.

WILLIAM O. SCHULTZ. 

